Large files. (hundreds of MBs or in the GBs) For many this isn't a use case, but if you do a lot of data loading, troubleshooting CSVs is a common need.
Is subl really that much faster at big CSV's for you? I made a quick 10 million line, ~1GB CSV in Python, opened it in both sublime text and code. code opened in 20seconds, subl took over a minute.
Honestly, it's been a while since I tried. Perhaps I'll take another stab at it and see how VS Code has improved. Out of curiosity, how wide is the file? Some of the files I open are 250+ field invoices, so each line is easily 1k characters each.
I used Sublime for like 5 years but VSCode is better in my opinion. With updates every month and a good support team. For free.